Aeroplane engines normally take thrust out into the airframe in two ways. Firstly, via the engine core either into a pylon or via thrust struts to the rear mount plane. Secondly, via a thrust trunnion on the fan case perpendicular to the engine access. With traditional under wing arrangements loads are taken rearwards through the engine or strut to the wing. With engines mounted towards the rear of the aeroplane matters can be more problematic as there is less airframe to receive thrust from the engine.